GOOPS is the object oriented extension to Guile. Its implementation is
derived from STk-3.99.3 by Erick Gallesio and version 1.3 of Gregor
Kiczales `Tiny-Clos'.  It is very close in spirit to CLOS, the Common
Lisp Object System (`CLtL2') but is adapted for the Scheme language.
While GOOPS is not compatible with any of these systems, GOOPS
contains a compatibility module which allows for execution of STKlos
programs.

Briefly stated, the GOOPS extension gives the user a full object
oriented system with multiple inheritance and generic functions with
multi-method dispatch.  Furthermore, the implementation relies on a
true meta object protocol, in the spirit of the one defined for CLOS
(Gregor Kiczales: A Metaobject Protocol).